Automated chemical analyzers have proven to be useful tools in clinical laboratory settings. Quantitative chemical analysis requires precise control of such factors as time of reaction, temperature and reagent concentration. Tests manually conducted typically lack precise control of these parameters resulting in inaccurate or irreproducible results. Additionally, manual testing limits the speed of processing, makes the handling of large numbers of samples difficult and introduces the possibility of human error, such as misidentification of samples.
Fully automated chemical analyzers automatically obtain a volume of a patient sample suspected of containing a particular analyte, add reagents to the sample and control reaction parameters such as time and temperature. Such analyzers usually include a transport or conveyor system designed to transport containers of reaction mixtures of sample and reagents to various operating stations. Reactions between analyte in the sample and reagents result in a detectable signal automatically measurable by the instrument. A number of automated chemical analyzers are currently available on the market. Volume 14 of the Journal of Clinical Immunoassay, Summer 1991, ("J. Clin. Immun."), the teachings of which are incorporated herein by reference, provides a description of several of such automated analyzers.
The transport mechanisms used in automated analyzers and similar equipment typically have several design constraints. For example, the size of the analyzer is optimally kept relatively small to minimize the space required by the analyzer in the laboratory. Hence, space is frequently at a premium and there is a significant incentive to keep the transport mechanisms used in such analyzers as compact as reasonably possible.
Additionally, if the vessels moved by these transport mechanisms are moved jerkily along a path, the contents of the vessels can splash either upwards along the vessel walls, or even out of the vessel. The accuracy of many automated analyzers can be adversely affected by such splashing either because a critical quantity of the solution is lost from the vessel or clings to the vessel walls and does not fully react with the other reagents in the vessel. Accordingly, transport mechanisms used in chemical analyzers and the like should advance the vessels along a chosen path relatively smoothly to avoid such splashing.
A variety of different vessel transport systems have been proposed for transporting reaction vessels through a chemical analyzer or the like. In most such systems, the vessels are held in rigid rings or by flexible belts. The rigid rings may comprise a ring having a planar support and a ring having a series of flanges which are rigidly attached to a rotating ring. By turning the ring, the fingers engage the vessels and move them along the support. The time a vessel spends on such a rigid ring is usually critical to some operation of the analyzer, such as incubating the vessels for a set period of time. In order to ensure a sufficient dwell time, the area occupied by such rigid rings in an analyzer tends to be relatively large.
Belt-based systems can also use a rigid support, but will use a flexible belt having flanges for engaging the vessels rather than a rigid ring. Although systems using belts could conceivably be made more compact than rigid rings due to the flexibility of the belts, most belt-based systems do not seem to have taken advantage of this flexibility to yield a more compact structure. In addition, the flexibility of the belts and the manner in which such belts tend to be driven within an analyzer tend to increase the possibility of splashing of the vessel contents if steps are not taken to ensure relatively smooth acceleration and deceleration of the belt as it moves along its path.
Accordingly, there is a need in the art to provide a stable, reliable system for transporting vessels in chemical analyzers and the like which will be compact and will minimize splashing of the contents of the vessels. As detailed below, a vessel transport system of the present invention provides a compact, reliable mechanism for transporting reaction vessels along a predefined path.